Fuel vapor processing device for internal combustion engine

Abstract

When purge control of fuel vapor, which is released from a fuel tank and is then adsorbed and retained in a fuel adsorption layer of a canister, is performed through ON/OFF control of a purge valve, ON/OFF of a heater plate received in the canister is controlled based on a purge fuel vapor concentration estimated through air-fuel ratio control operation of an engine. In this way, a sensor for measuring the purge fuel vapor concentration of the fuel vapor conducted from the canister to an intake passage of the engine can be eliminated.

What is claimed is:  
     
       1. A fuel vapor processing device for an internal combustion engine, the fuel vapor processing device comprising: 
       a canister that includes:  
       a case; and  
       a fuel adsorption layer that is received in the case and includes an adsorption material for adsorbing fuel vapor, wherein one end of the case is communicated with a fuel vapor passage connected to a fuel tank and is also communicated with a purge passage connected to an intake passage of the internal combustion engine, and the other end of the case is communicated with the atmosphere;  
       a purge control means for:  
       enabling temporary adsorption and retainment of fuel vapor, which is released from the fuel tank to the fuel vapor passage, in the fuel adsorption layer; and  
       enabling desorption and conduction of the fuel vapor from the fuel adsorption layer into the intake passage through the purge passage during operation of the internal combustion engine;  
       a temperature adjusting means for adjusting the temperature of the fuel adsorption layer; and  
       an activation control means for controlling activation and deactivation of the temperature adjusting means based on an adsorbed amount of fuel vapor adsorbed and retained in the fuel adsorption layer;  
       wherein the activation control means calculates the adsorbed amount of fuel vapor based on the amount of fuel in the fuel tank to control activation and deactivation of the temperature adjusting means.  
     
     
       2. A fuel vapor processing device for an internal combustion engine, the fuel vapor processing device comprising: 
       a canister that includes:  
       a case; and  
       a fuel adsorption layer that is received in the case and includes an adsorption material for adsorbing fuel vapor, wherein one end of the case is communicated with a fuel vapor passage connected to a fuel tank and is also communicated with a purge passage connected to an intake passage of the internal combustion engine, and the other end of the case is communicated with the atmosphere;  
       a purge control means for:  
       enabling temporary adsorption and retainment of fuel vapor, which is released from the fuel tank to the fuel vapor passage, in the fuel adsorption layer; and  
       enabling desorption and conduction of the fuel vapor from the fuel adsorption layer into the intake passage through the purge passage during operation of the internal combustion engine;  
       a temperature adjusting means for adjusting the temperature of the fuel adsorption layer; and  
       an activation control means for controlling activation and deactivation of the temperature adjusting means based on an adsorbed amount of fuel vapor adsorbed and retained in the fuel adsorption layer;  
       wherein the activation control means calculates the adsorbed amount of fuel vapor based on a non-operating time period of the internal combustion engine to control activation and deactivation of the temperature adjusting means.  
     
     
       3. A fuel vapor processing device for an internal combustion engine, the fuel vapor processing device comprising: 
       a canister that includes:  
       a case; and  
       a fuel adsorption layer that is received in the case and includes an adsorption material for adsorbing fuel vapor, wherein one end of the case is communicated with a fuel vapor passage connected to a fuel tank and is also communicated with a purge passage connected to an intake passage of the internal combustion engine, and the other end of the case is communicated with the atmosphere;  
       a purge control means for:  
       enabling temporary adsorption and retainment of fuel vapor, which is released from the fuel tank to the fuel vapor passage in the fuel adsorption layer; and  
       enabling desorption and conduction of the fuel vapor from the fuel adsorption layer into the intake passage through the purge passage during operation of the internal combustion engine;  
       a temperature adjusting means for adjusting the temperature of the fuel adsorption layer; and  
       an activation control means for controlling activation and deactivation of the temperature adjusting means based on an adsorbed amount of fuel vapor adsorbed and retained in the fuel adsorption layer;  
       wherein the activation control means calculates the adsorbed amount of fuel vapor based on a temperature variation in the canister to control activation and deactivation of the temperature adjusting means.  
     
     
       4. A method for effecting an improved fuel vapor adsorption and purging process in connection with an internal combustion engine using a canister that includes a case containing fuel vapor adsorption material communicating with (a) a fuel tank vapor passage, (b) an engine intake fuel vapor purge passage and (c) the atmosphere, said method comprising: 
       enabling temporary adsorption and retainment of fuel vapor, which is released from the fuel tank to the fuel vapor passage, in the fuel adsorption material;  
       enabling desorption and conduction of the fuel vapor from the fuel adsorption material into the intake passage through the purge passage during operation of the internal combustion engine;  
       adjusting the temperature of the fuel adsorption material;  
       controlling activation and deactivation of the temperature adjusting step based on an adsorbed amount of fuel vapor adsorbed and retained in the fuel adsorption material;  
       wherein the activation controlling step includes calculating the adsorbed amount of fuel vapor based on the amount of fuel in the fuel tank to control activation and deactivation of the temperature adjusting step.  
     
     
       5. A method for effecting an improved fuel vapor adsorption and purging process in connection with an internal combustion engine using a canister that includes a case containing fuel vapor adsorption material communicating with (a) a fuel tank vapor passage, (b) an engine intake fuel vapor purge passage and (c) the atmosphere, said method comprising: 
       enabling temporary adsorption and retainment of fuel vapor, which is released from the fuel tank to the fuel vapor passage, in the fuel adsorption material;  
       enabling desorption and conduction of the fuel vapor from the fuel adsorption material into the intake passage through the purge passage during operation of the internal combustion engine;  
       adjusting the temperature of the fuel adsorption material;  
       controlling activation and deactivation of the temperature adjusting step based on an adsorbed amount of fuel vapor adsorbed and retained in the fuel adsorption material;  
       wherein the activation controlling step includes calculating an adsorbed amount of fuel vapor based on a non-operating time period of the internal combustion engine to control activation and deactivation of the temperature adjusting step.  
     
     
       6. A method for effecting an improved fuel vapor adsorption and purging process in connection with an internal combustion engine using a canister that includes a case containing fuel vapor adsorption material communicating with (a) a fuel tank vapor passage, (b) an engine intake fuel vapor purge passage and (c) the atmosphere, said method comprising: 
       enabling temporary adsorption and retainment of fuel vapor, which is released from the fuel tank to the fuel vapor passage, in the fuel adsorption material;  
       enabling desorption and conduction of the fuel vapor from the fuel adsorption material into the intake passage through the purge passage during operation of the internal combustion engine;  
       adjusting the temperature of the fuel adsorption material;  
       controlling activation and deactivation of the temperature adjusting step based on an adsorbed amount of fuel vapor adsorbed and retained in the fuel adsorption material;  
       wherein the activation controlling step includes calculating an adsorbed amount of fuel vapor based on temperature variation in the canister to control activation and deactivation of the temperature adjusting step.